Getting Quality Sleep

Issue 99 December 2012

Sleeping right can be just as important as leading a healthy lifestyle. Mohammed Latif explores the different types of sleep, common sleeping issues, and how to ensure that you have good sleep hygiene.

Approximately one-third of an average life span is spent sleeping. The importance of sleep varies between individuals. Some people only need fours hours a night, with Margaret Thatcher a famous example, whilst most of us will struggle at less than eight hours. But it isn't only the quantity; the quality of sleep also matters quite significantly.

Types of Sleep

Sleep has been divided into two types: Rapid Eye Movement (REM) and non-Rapid Eye Movement sleep. We start off at non-REM sleep of which there are three stages. Stage 1 describes the transition between sleep and wakefulness, with some preserved awareness of surroundings and active muscle tone. Stage 2 is characterised by darting eye movements and disappearing awareness of external environment, leading on to Stage 3, which is commonly known as 'deep sleep'. These stages can be identified by specific waveforms seen on polysomnography, a method of evaluating brain electrical activity using external electrodes as part of a full sleep study.

What usually follows Stage 3 is REM sleep. This phase accounts for 25% of total sleep time and is when our most memorable dreaming happens. We also lose muscle tone and are effectively paralysed. We display the characteristic 'Rapid Eye Movements' after which this phase is named. During sleep, we cycle between these stages and on average five of these cycles occur during sleep with the frequency of REM episodes increasing towards waking time. The complexity of cycling between the stages and the physiological changes associated are best manifested by some complaints people have about their sleep. For example, the transition from wakefulness to sleep during Stage 1 can elicit visual or auditory hallucinations. 'Falling' sensations and subsequent muscle jerks and kicks can occur because the body misinterprets the lowered muscle tone as sleep approaches the REM stage. Sleep paralysis is a phenomenon where a person has disrupted REM sleep and hasn't recovered muscle tone in time. This can be accompanied by hallucinations as the body is still transitioning between REM sleep and wakefulness.

Sleeping Problems

The most common sleep complaint is insomnia. This is defined as 'sleeping difficulties' and encompasses both quality and quantity of sleep, lasting for a month and affecting quality of life. Insomnia can be a result of either physical or mental problems but is often found to occur without any cause. The incidence increases with age. Common causes include stress, medication, disturbances in sleep rhythm, such as jet-lag, and poor sleep hygiene. It is no surprise that chronic diseases such as arthritis or back pain can also disturb sleep.